Inclined plane/Static Friction Problem

1. A 250-kg crate rests on a surface that is inclined above the horizontal at an angle of 21.8°. A horizontal force (magnitude = 515 N and parallel to the ground, not the incline) is required to start the crate moving down the incline. What is the coefficient of static friction between the crate and the incline?

2. Ff=μsmgcosθ
Fapplied=Fparallelcosθ

3. I made Fparallel equal to Ff. When I solved it I got a coefficient of static friction of .244, but apparently it's not correct.